The Canadian company pumped the line’s west segment with water and kept pressure high for 8 hours. Enbridge officials told reporters in a conference call Monday that the line is fit for service and no leaks were found.

A second pipeline, called the east segment, will be tested soon.

The pipelines where Lake Huron and Lake Michigan converge were built in 1953. Line 5 carries about 23 million gallons (19 million imperial gallons) of crude oil and liquid natural gas daily between Superior, Wisconsin, and Sarnia, Ontario.